Each year on this day, the saint's death is marked, along with all things Irish, in his home country and across the world.
At times along the coastal route there is a mere two-car width between you and the sea. Turn a corner, however, and it opens up to typical Irish glens, complete with rolling green hills, fields and sheep - everything travellers picture Ireland to be.
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The coastal drive starts from Belfast, the beating heart of County Antrim and Northern Ireland's capital city. The RMS Titanic was built in this port city: "she was fine when she left here," locals like to quip. A century later, the iconic new Titanic Belfast visitor attraction is the centrepiece of a rejuvenated quarter named after the ill-fated liner. If 20th century Belfast was stifled by political strife, today it's energetic and outward looking. It has hosted Lady Gaga and the MTV Europe Music Awards. It is home to the new Metropolitan Arts Centre and to gleaming hotels and shopping malls. Former no-go areas, such as the Falls and Shankill Roads, are now the focus of brilliant Black Taxi Tours.
Beyond Belfast to Ballymena - 88.6km
Follow the Causeway Coastal Route signs on the M2 to Larne, gateway to the famous Glens of Antrim. Here you can take the loop around Island Magee to Portmuck Harbour and the Gobbins Cliffs, home to myriad seabirds. At Newtownabbey's Laughshore Park, take in the remarkable sight of ships sailing from Belfast. This is where the fateful Titanic first sailed as it headed out from the famous shipyards of Harland & Wolf.
A few miles on at the pretty seaside town of Carrickfergus, is Ireland's oldest and most well-preserved 12th century Norman castle.
From there head north for the picturesque village of Ballygally. The brave can visit the "ghost" room in the Hastings Ballygally Castle Hotel, supposedly haunted by a friendly ghost.
At the foot of Glenarm Glen sits Glenarm Castle, one of Ireland's oldest estates, with its splendid walled gardens. Take the opportunity to head inland through the flower-filled village of Broughshane and clamber up Slemish Mountain, where St Patrick is said to have tended livestock as a slave boy in the fifth century.
Ballymena to Ballycastle - 72.2km
Returning to the coast, immerse yourself in the splendour of the Glens of Antrim.
Discover Glenariff (Queen of the Glens) with its forest park where four walking trails lead you through a fairytale landscape of leafy glades and tumbling waterfalls. Continue on the Causeway Coastal Route to the village of Carnlough with its picturesque harbour overlooking Carnlough Bay. Carnlough's main street boasts the Londonderry Arms Hotel.
Built in 1848 as a coaching inn, it's a superb example of Georgian architecture and enjoys a famous former owner in the portly shape of Sir Winston Churchill. You can stay in one of the executive rooms favoured by the former Prime Minister.
From there, head to Ballycastle, visiting Cushendun, the Vanishing Lake and Ballypatrick Forest Park. The narrow road from Cushendun to Torr Head is a switchback considered one of the finest sections of coastal road in Ireland.
Alternatively head inland to Ballymoney, the home of motorcycle racing legends the Dunlop brothers. Memorial gardens to the famous brothers, Joey and Robert, can be found in the town. Outside the village of Armoy (close to Gracehill Golf Club) is a haunting avenue of trees known as The Dark Hedges.
Back on the coastal route, take a stroll along the seafront of Ballycastle, with Rathlin Island and Scotland in the distance.
Ballycastle to Portrush - 31km
From here you have the option of a short ferry crossing to Rathlin Island (where Robert the Bruce took refuge) or head for Carrick-a-Rede Rope Bridge suspended across a 20m chasm. Originally erected by fishermen to check salmon nets, today the structure takes you on a precarious path over a 20m-wide (and 23m-deep) chasm to Carrick Island. Try not to look down. If you do, don't fret.
Back on solid ground, a stiff whiskey awaits at the Old Bushmills whiskey distillery (Ireland's oldest) to calm the nerves. From Carrick-a-Rede, it's a short hop to the magnificent Giant's Causeway, one of the most recognisable Unesco World Heritage sites in Western Europe and a highlight of the drive.
If you go along with Lonely Planet's take on Northern Ireland's north coast as "a giant geology classroom", then the Giant's Causeway is lesson number one. Taking the form of 40,000 basalt columns cascading into the Irish Sea, the Causeway was created by millions of years of volcanic and geologic activity.
Or, if you prefer, by mythical giant Fionn mac Cumhaill as a series of steps to transport him to Scotland. A new visitor centre gives the lowdown on both versions.
On the approach to Portrush, is Dunluce Castle, perched precariously on the clifftop overlooking this seaside resort, one of Ireland's most iconic and historic sights.
Portrush to Limavadyy - 31.5km
Take a short drive to Portstewart, and inland to the university town of Coleraine and home of one of the oldest known human settlements in Ireland at Mountsandel on the banks of the River Bann. As the coastal route winds onward to Limavady, you will pass by Castlerock.
Keep an eye out for Hezlett House, a 17th-century thatched cottage, and the glorious Mussenden Temple. The clifftop folly was inspired by the Tivoli Temple of Vesta at Rome.
Limavady to Londonderry - 27.3km
Take a bracing walk on Binevenagh Mountain to enjoy panoramic views. The vibrant market town of Limavady is a great spot for a mosey. Before leaving Limavady, take a detour to explore the magnificent Roe Valley Country Park. The route finishes in Londonderry, the only completely walled city in Ireland. It's been named the UK City of Culture for this year and offers a range of interesting events throughout the year.
